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Wednesday, October 31, 2007

TOXIC SHOCK SYNDROME: THE EPIDEMIOLOGY

IntroductionToxic Shock syndrome (TSS) is a rare but potentially fatal multisystem disease caused by bacterial toxin of staphylococci (commonly staphylococcus aureus with vastly due to TSS toxin-1, enterotoxin B and enterotoxin C) and streptococci (commonly streptococcus pyogenes which due to exotoxin A and exotoxin B). Although this syndrome has occurred long ago, this condition was only first been described by Todd and Fishaut in 1978, to have been associated with a strain of staphylococcus bacteria. Cases of TSS caused by streptococci were first reported in the mid 1980s.

HistoryIn 1978, Dr J. K. Todd first described the illness in three boys and four girls aged 8-17 years. Even though S. aureus was isolated from mucosal sites from the patients, it could not be isolated from the blood, cerebrospinal fluid, or urine, raising suspicion that a toxin was involved.

Investigations conducted later noted that reports of similar illnesses had appeared occasionally as far back as 1927. Most notably, at the time he failed to consider the possibility of a connection between toxic shock syndrome and tampon use, as three of the girls who were menstruating when the illness developed were using tampons.

Following a controversial test marketing, in August 1978 Procter and Gamble introduced hyperabsorbent Rely tampons to the United States market in response to women's demands for tampons that could contain an entire menstrual flow without leaking or replacement. The tampons used carboxymethylcellulose (CMC) and compressed beads of polyester for absorption. Use of hyperabsorbent tampons creates environment suitable for production of staphylococcal TSS where there is an increase in vaginal partial pressure of oxygen, thus stimulating toxin synthesis. Tampons also bind magnesium and shift the growth kinetics of S aureus to increase toxin production.

In January 1980, epidemiologists reported the appearance of staphylococcal TSS, mostly in menstruating women, to the Centers for Disease Control and Prevention (CDC) in Atlanta. In September 1980, the CDC reported that users of Rely were at increased risk for developing TSS. On September 22, 1980, Procter and Gamble recalled Rely following release of the CDC report. It was shown later that higher absorbency of tampons was associated with an increased the risk for TSS, regardless of the chemical composition or the brand of the tampon. For the period of 1970 to 1982, CDC reported 1700 cases with 96% involving women. This was therefore considered an epidemic in the United States then. The ability of carboxymethylcellulose to filter the S. aureus toxin that causes TSS may account for the increased risk associated with Rely. By the end of 1980, the number of TSS cases reported to the CDC began to decline. This was attributed not only to the removal of Rely from the market, but also from the diminished use of all tampon brands. However, there is an increase of incidence involving nonmenstrual TSS where herniorrhaphy, mammoplasty, arthroscopy, and other surgical wound infections may be complicated by the development of TSS with manifestations of TSS usually begin 2 days after surgery.

The Disease ItselfTSS is manifests with high grade fever, rashes, vomit, diarrhea, muscle ache, mucous membrane hyperemia, mental confusion, renal dysfunction, low blood pressure of below 90mmHg, hepatic anomalies and thrombocytopenia, where multisystem involvement is common. Onset of TSS is usually abrupt. Annual incidence of staphylococcal TSS in United States is 1-5 cases per 100,000 menstruating women. An estimated 77-93% of cases occur in women (41% occur in females aged 13-19 years). Meanwhile, the incidence of streptococcal TSS is 5-10 cases per 100,000 populations. Over the years, epidemiologists have reported that the mortality rate in patients with S aureus TSS is approximately 3.3% while rate in patients with streptococcal TSS is approximately 30%. Staphylococcal TSS is more common in females during menstruation while nonmenstrual TSS is 3 times more common in females than in males However; Streptococcal TSS affects males and females. Staphylococcal TSS is common in people aged 15-35 years. More than 90% of cases in women occur in those aged 15-19 years. Streptococcal TSS is seen in all age groups; however, most cases occur in people aged 20-50 years.

Pathogenesis20-30% of healthy people carry S. aureus in their nose, however can colonize skin or vagina, exacerbate with the use of tampons, foreign bodies and wound, providing a site where bacteria multiply and toxins production are possible. Another emerging cause is wound infections following childbirth and abortion. For years, women are still a risk group for TSS, along with hospitalized patients with wounds or bedsores.

Treatment and preventionTreatment for patients suffering from TSS is with supportive hospital care, removal of foreign bodies and administration of anti-Staphylococcal antibiotics. Patients who had episodes of TSS can develop recurrence of TSS episodes. There is recent development for vaccination for prophylaxis.